Heat output and tumbling action ceased working after approximately 20-30 minutes of use.

Removed and replaced motor. In the process of removing old motor, the blower wheel had to be unscrewed from the rear shaft of the motor, in order to remove the motor. In my case, the blower wheel had seized up on the rear shaft and could not be unscrewed. It had to be cut off and it also had to be replaced. The dryer now works fine. Tip: I watched an internet video (repairclinic.com)about the procedure before I started. Very helpful!